How would I go about rigging this?
First enable the Rigify Addon in Menu: File / User Preferences



Now you can add the whole human rig to your scene in Object Mode Shift-A



In Edit Mode align all bones with your model. When done parent the model to the rig Ctrl-P (With Automatic Weights).



And create the Meta-Rig.



After that you can create Actions and arrange them in the NLA editor. Importing to Unity is best done by Import New Asset from the Asset Menu.

A more detailed description with removal of unneeded bones is available in the Unity documentation: http://docs.unity3d.com/Manual/BlenderAndRigify.html



If you don't want to animate a humanoid then chose Animation Type: Generic  in the import settings of the rig: